The combined properties of good electrical insulation, high thermal conductivity, and low dielectric constant make diamond well suited for use in electronic device packaging and multichip module technologies. The deposition of micro, nano and ultrananocrystalline diamond has been reported on various kinds of substrates. The substrates can be classified into three groups viz. ones that form carbides (Si, Mo, W); those which dissolve carbon but do not form carbides (Pt, Pd, Rh); and those which neither dissolve carbon nor form carbides (Cu, Ag, Au). Diamond films on Cu substrates or Cu surfaces are of significant interest with respect to present-day electronics (copper interconnects) and microelectronics. The growth of well-adhered and dense diamond films on non-carbide forming and non-carbon dissolving substrates or surfaces like Cu Ag, Au is important in view of electrical applications but it is usually considered impractical because of poor adhesion, low nucleation density, and their immiscibility with carbon.
Diamond nucleation on non-diamond surfaces without pre-treatment is usually very difficult and slow. Various methods are employed in the existing art to improve the nucleation density. Diamond nucleation on non-diamond surfaces can be enhanced by the surface pretreatments including scratching, seeding, electrical biasing, ion implantation, ultrasonic abrasion with diamond powder mixture suspensions and pre-coating silicon substrate nucleation layers such as tungsten followed by ultrasonic agitation with nanodiamond powder.
It is a well established fact known to those skilled in the art that the nucleation density is enhanced by various pre-treatment methods but at the same time, the surface alteration or damage (usually by the formation of nano-scale pits and scratches and defect concentration) and contamination of the substrate surface in varying degrees as a result of any kind of pre-treatment cannot be overruled and is inevitable. Also, these pretreatment methods cannot be easily applied to substrates of complex geometry and shape, and are incompatible with many real-life applications requiring such diamond films viz. electronic devices, and optical window materials and they even add to the expenditure. Thus, pre-treatment of the substrate surface to enhance nucleation density renders it unsuitable for integration into electronics line of production.
Hence, there exists the need of an effective method of diamond nucleation on an electrically viable surface that does not require any pre-treatment and exhibits high nucleation density. The present invention overcomes the drawbacks of the pre-treatment methods and leads to the direct integration of diamond in electronic chips and also reduces the production cost.